/// <summary>
/// Given a FEN, return a list of ChessPiece objects descibed by the FEN
/// </summary>
/// <param name="fen">FEN input</param>
/// <returns>ChessPieces contained in the FEN description</returns>
public static List <ChessPiece> ExtractPieces(string fen)
{
string[] fenTokens = TokenizeFEN(fen);
// The first part describes the pieces...
string fenString = fenTokens[0];
// Create a new list for the pieces we'll find
List <ChessPiece> pieces = new List <ChessPiece>();
int currentRank = 8; // 8 - back rank for Black
int currentFile = 1; // A
int index = 0;
// Token can be 1-8 characters long per rank plus separators, so not long
while (index < fenString.Length)
{
char fenChar = fenString[index++]; // Save the current char
if (Char.IsLetter(fenChar))
{
// Uppercase is white, lower black
PieceColor color = Char.IsUpper(fenChar) ? PieceColor.White : PieceColor.Black;
// Create the new ChessPiece object at the given location
ChessPiece newPiece = new ChessPiece(color,
ChessBoard.PieceClassFromFen(fenChar), new PieceFile(currentFile), currentRank);
// Need to update deployed for pawns not on their home ranks
if (newPiece.Job == PieceClass.Pawn)
{
int homeRank = (newPiece.Color == PieceColor.White) ? 2 : 7;
if (newPiece.Rank != homeRank)
{
newPiece.Deployed = true;
}
}
pieces.Add(newPiece); // Add it to our total list of pieces
currentFile++;
}
else if (Char.IsDigit(fenChar))
{
// Digits represent empty squares and are RLE (run length encoded) like a bitmap
// advance File the amount of the spaces specified
currentFile += (Convert.ToUInt16(fenChar) - Convert.ToUInt16('0'));
}
else if (fenChar == '/')
{
// The '/' denotes the end of a rank on the chess board
// decrement Rank and reset the File (like a newline)
currentRank--;
currentFile = 1;
}
}
// Return all of the pieces found
return(pieces);
}
/// <summary>
/// Invoked when the chess engine has responded with a move to apply to the
/// local board
/// </summary>
private void OnEngineBestMoveResponse()
{
thinkingIndex = 0; // reset index counter for simple progress text
// Get the best move from the engine
string bestMove = engine.BestMove;
if ((String.Compare(bestMove, "(none)") == 0) || // Stockfish (and converted ones)
(String.Compare(bestMove, "a1a1") == 0) || // Rybka
(board.HalfMoveCount >= HalfMovesUntilDraw)) // Propably spinning on self play or just a draw
{
if (board.HalfMoveCount >= HalfMovesUntilDraw)
{
Debug.WriteLine("Draw by 50 moves rule...");
}
GameOverHandler();
}
else if (GetInputState() == InputState.WaitingOnOpponentMove)
{
// Extract the board location from the move string
PieceFile startFile = new PieceFile(bestMove[0]);
int startRank = Convert.ToInt16(bestMove[1]) - Convert.ToInt16('0');
PieceFile destFile = new PieceFile(bestMove[2]);
int destRank = Convert.ToInt16(bestMove[3]) - Convert.ToInt16('0');
ChessPiece foundPiece = board.FindPieceAt(startFile, startRank);
MoveInformation moveInfo = new MoveInformation(
new BoardSquare(startFile, startRank),
new BoardSquare(destFile, destRank),
foundPiece.Deployed, board.CurrentFEN);
moveInfo.Color = foundPiece.Color;
moveInfo.CastlingRights = board.ActivePlayerCastlingRights;
// When coming from the engine, we get the promotion detection for free
if (bestMove.Length == 5)
{
// Applied on the next move
PieceClass promotionJob = ChessBoard.PieceClassFromFen(bestMove[4]);
board.PromotePiece(startFile, startRank, destFile, destRank, promotionJob, ref moveInfo);
}
// Move the piece on the board, and add it to the official moves list
board.MovePiece(ref moveInfo);
// trigger a redraw
view.Invalidate();
// Apply the move the engine just gave us with the engine (update it's own move)
UpdateEnginePosition();
}
}